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How does mysql modify a row of data in a data table? This problem may be often seen in our daily study or work. I hope you can gain a lot from this question. The following is the reference content that the editor brings to you, let's take a look at it!

The method of modifying a row of data in a data table in mysql: use update statement, syntax format "UPDATE SET field 1 = value 1 [, field 2 = value 2 …] [WHERE clause] [ORDER BY clause] [LIMIT clause]".

In MySQL, you can use UPDATE statements to modify and update the data of one or more tables.

Basic syntax of UPDATE statements

Use the UPDATE statement to modify a single table in the syntax format:

UPDATE SET field 1 = value 1 [, field 2 = value 2... [WHERE clause] [ORDER BY clause] [LIMIT clause]

The syntax is as follows:

Used to specify the name of the table to update

SET clause: used to specify the column name to be modified in the table and its column value. Where each specified column value can be an expression or a default value for that column. If the default value is specified, the DEFAULT keyword is available to indicate the column value.

WHERE clause: optional. Used to limit the rows in the table to be modified. If not specified, all rows in the table are modified.

ORDER BY clause: optional. Used to limit the order in which rows in the table are modified.

LIMIT clause: optional. Used to limit the number of rows to be modified.

Note: when you modify multiple column values for a row of data, each value of the SET clause can be separated by a comma.

Modify the data in the table according to conditions

Example: in the tb_courses table, update the record with a course_id value of 2, change the course_grade field value to 3.5, and change the course_name field value to "DB". The SQL statement entered and the execution result are shown below.

Mysql > UPDATE tb_courses_new-> SET course_name='DB',course_grade=3.5-> WHERE course_id=2;Query OK, 1 row affected (0.13 sec) Rows matched: 1 Changed: 1 Warnings: 0mysql > SELECT * FROM tb_courses_new +-+ | course_id | course_name | course_grade | course_info | +-+ -+ | 1 | Network | 4 | Computer Network | | 2 | DB | 3.5 | MySQL | 3 | Java | 4 | Java EE | | 4 | System | 4 | Operating System | +- -+ 4 rows in set (0.00 sec)

Note: make sure that the UPDATE ends with the WHERE clause, and specify the conditions that the updated record needs to meet through the WHERE clause. If you omit the WHERE clause, MySQL will update all rows in the table.

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